the CCS811 is an ultra-low-power digital gas sensor that integrates a sensor and a CCS801-bit MCU with an analog-digital converter (ADC) for detecting indoor air quality, including carbon monoxide (CO) and a wide range of Volatile Organic compounds (VOCs) SCL: I2C serial clock SDA: I2C serial data WAK: Low level is effective. The sensor will not start working until it is pulled low INT: Low level is effective, after the program of CCS811 chip runs,it can be grounded reset RST: Low level is effective, the module is pulled up to VDD by default ADD: Single address selection bits allow alternative addresses to be selected When the l2C address is low, the 7-bit address is 0x5a When the l2c address is high, the 7-bit address is 0x5b